280 AI load development

8andbait

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Started working up loads for a new rifle in 280 AI.
E85539DF-BC75-444B-95E9-AFD3238F806D.png
Tim Mc Whorter at flat creek precision did the build.
We used a fluted #4 brux 9 twist at 24" custom throated for 175 elite hunters. Unfortunately I have not been able to acquire any 175's so I started with 168 VLDH.

New Peterson brass was a crush fit so I pushed the shoulder back .002 on the new brass.
Intention was to establish a rough zero and get all 100 brass fired and some rounds on the barrel.
I started mid 50's with rl23 and cci250 primers.

Fired a few rounds and then worked my way up to 59 grains with the 168 at .030 jump. Never saw any pressure and the groups were decent but not great.

One thing I noticed is that RL23 fills the case quickly, 59 is bordering on compressed with a standard funnel.

After that I backed off to 57 grains and loaded for seating depth.
.010 jam
.010 jump
.050 jump
.090 jump
All were decent but .010 jump and .050 were both in the .4s so I went with .010 jump.

After that I did an OCW type test from 56.2 to 58 grains.
56.5 looked like the place to be, velocity was 2870 fps in the new brass.
I then tested primers with the same load and five shot groups.
CCI 250, CCI BR2 and 210M were tested which revealed very similar groups but the BR2 were slightly better.

Tried a few loads with RL26 and the 168's which was fairly uneventful except 58.5 gains which shot a tiny .058" group but I'm sure the speed was mid 2800's at best. I only have a couple pounds of 26 so not really going to pursue that.

After that I finished shooting the new brass with sierra 150 TGK's with RL23, RL26 and N565.
RL26 and N565 leave plenty of room in the brass compared to RL23.
I only shot increasing charge weights over the magnetospeed, so no groups. Rl26 and n565 were fairly slow with the 150's (high 2900's) but I just wanted to experiment so see where to start if I went that direction later on. Rl23 on the other hand was 3075 fps with 58.6 grains (compressed) and no pressure signs.

I now had 100 once fired brass and 100 rounds on the barrel so time to get a little more serious.

I cleaned the barrel and resized the brass to bump the shoulder .002 and size the necks to .311 which is .002 under the loaded dimension.

Using 1x Peterson brass, RL23, BR2 and 168 vld at .010 jump, I loaded 3 foulers at 58, 58.3 and 58.6 then groups of 57.7, 58, 58.3 and 58.6.
I shot the foulers over the chrono,
58, 2943
58.3, 2957
58.6, 2967

Shot all the groups while cooling 10 minutes between 3 shot groups.
All were on the same horizontal plane and under .7", they got smaller as they approached 58.6 which is .358"
08B323F3-B147-40E9-A81C-3823696720A0.jpeg
I'll use this load for the next 50 rounds then check precision and velocity again if needed.

I know this jumped around a little but hopefully this will help someone with some of these components find a starting point.
 
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My 280ai liked H-4831SC and Reloder 22 with Barnes 120 gr TSX and the 145 LRX. The LRX shot amazing with groups running .5-.6. It was hard to make this bullet shoot bad. I left the 120 TTSX because the tips would wobble when rolled on the benchtop. The tsx shot better groups and no difference in performance on game as far as I could tell with H-4831SC giving .16"
 
8andbait - thanks for posting this info. I will hopefully be going down the same path in the not too distant future. It will be my first 280ai. I have a fairly broad range of powders, but limited quantities in each (except for H4831sc and IMR4831). It is always good to have starting point to start the load development. Now I need to find some Redding dies and wait for the action to get to my GS to get this thing built.
 
Had an hour this morning to check cold bore zero. I haven't shot further than 100 yards yet so I didn't have a true 200 yard zero.
I had a little left to right wind and and a slight updraft for the last 80 yards. First and only two I fired today. I moved the scope up 1/4 MOA.




48EBFC2E-BDCF-4D4F-85A5-4918C33737FC.jpeg
 
Started working up loads for a new rifle in 280 AI.
View attachment 348083
Tim Mc Whorter at flat creek precision did the build.
We used a fluted #4 brux 9 twist at 24" custom throated for 175 elite hunters. Unfortunately I have not been able to acquire any 175's so I started with 168 VLDH.

New Peterson brass was a crush fit so I pushed the shoulder back .002 on the new brass.
Intention was to establish a rough zero and get all 100 brass fired and some rounds on the barrel.
I started mid 50's with rl23 and cci250 primers.

Fired a few rounds and then worked my way up to 59 grains with the 168 at .030 jump. Never saw any pressure and the groups were decent but not great.

One thing I noticed is that RL23 fills the case quickly, 59 is bordering on compressed with a standard funnel.

After that I backed off to 57 grains and loaded for seating depth.
.010 jam
.010 jump
.050 jump
.090 jump
All were decent but .010 jump and .050 were both in the .4s so I went with .010 jump.

After that I did an OCW type test from 56.2 to 58 grains.
56.5 looked like the place to be, velocity was 2870 fps in the new brass.
I then tested primers with the same load and five shot groups.
CCI 250, CCI BR2 and 210M were tested which revealed very similar groups but the BR2 were slightly better.

Tried a few loads with RL26 and the 168's which was fairly uneventful except 58.5 gains which shot a tiny .058" group but I'm sure the speed was mid 2800's at best. I only have a couple pounds of 26 so not really going to pursue that.

After that I finished shooting the new brass with sierra 150 TGK's with RL23, RL26 and N565.
RL26 and N565 leave plenty of room in the brass compared to RL23.
I only shot increasing charge weights over the magnetospeed, so no groups. Rl26 and n565 were fairly slow with the 150's (high 2900's) but I just wanted to experiment so see where to start if I went that direction later on. Rl23 on the other hand was 3075 fps with 58.6 grains (compressed) and no pressure signs.

I now had 100 once fired brass and 100 rounds on the barrel so time to get a little more serious.

I cleaned the barrel and resized the brass to bump the shoulder .002 and size the necks to .311 which is .002 under the loaded dimension.

Using 1x Peterson brass, RL23, BR2 and 168 vld at .010 jump, I loaded 3 foulers at 58, 58.3 and 58.6 then groups of 57.7, 58, 58.3 and 58.6.
I shot the foulers over the chrono,
58, 2943
58.3, 2957
58.6, 2967

Shot all the groups while cooling 10 minutes between 3 shot groups.
All were on the same horizontal plane and under .7", they got smaller as they approached 58.6 which is .358"
View attachment 348082
I'll use this load for the next 50 rounds then check precision and velocity again if needed.

I know this jumped around a little but hopefully this will help someone with some of these components find a starting point.
Thanks. Very helpful as I'm almost out of 160 Nosler AB's and have began working on Berger 168's as I have a few hundred. I went straight to RL 26 and had great accuracy with 58.5 but went south with increase. Plenty of case left. I have a few pounds of RL23 so I will give it go. I'm primarily a hunter who enjoys to shoot. Bergers shoot great but sure can destroy meat with any shot except head. AB's have been great accuracy wise and in the field with minimal collateral damage with a proper placed shot (which doesn't happen all the time). Reading great Hammer results. Great choice with the .280AI
 
I plan on stuffing my 280 AI ultralight full of H1000. I started with new Peterson brass and 180gr ELDs. Just a middling load of H1000, but nothing shot over an inch at 100 so I kept it at either 56/57gr and just am doing a seating test.

Sometimes it's a pain breaking in a new rifle, but at least you can dial in little things while seasoning the barrel!

So far loving the rifle.
 
I plan on stuffing my 280 AI ultralight full of H1000. I started with new Peterson brass and 180gr ELDs. Just a middling load of H1000, but nothing shot over an inch at 100 so I kept it at either 56/57gr and just am doing a seating test.

Sometimes it's a pain breaking in a new rifle, but at least you can dial in little things while seasoning the barrel!

So far loving the rifle.
I tested H-1000 in mine with 145 LRX and 120 TSX. Both bullets shot .6" and damaged minimal meat while destroying the lungs. Looked like a blender blade spun thru them. Exit hole had bloodshot meat out to about 1" from edge of the hole
 
New brass, 150 TGK@ .020, 210M

N565/FPS
58.5-2807
59.0-2833
59.5-2864
60.0-2906
60.5-2940

RL23/FPS
56.0-3014
56.5-3034
57.5-3046
58.0-3077
58.5-3075
 
I tested H-1000 in mine with 145 LRX and 120 TSX. Both bullets shot .6" and damaged minimal meat while destroying the lungs. Looked like a blender blade spun thru them. Exit hole had bloodshot meat out to about 1" from edge of the hole
How was the velocity? I plan on using hammers unless the 145lrx shoot significantly better. I use the HH out of my heavy 7mm RM. Took two deer last year with it, very clean killing bullet.
 
8andbait, thanks for posting.

One thing I noticed is that RL23 fills the case quickly, 59 is bordering on compressed with a standard funnel.

I found the same thing when loading my Nosler brass for 140TSX for my 280AI Kimber Montana. Short throat on this one.

I plan to work with the limited amount of RE22 that yielded good results but looking to see if N560 and/or H4831 are good choices.
 
Thank You 8and bait for posting.. In my 280AI I;m shooting peterson brass 143HH with 59.5gr RL23 .010 off getting 3110fps and .6 for 5 shots at 200yds
 
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